ABSTRACT

Human perception and vision have evolved in response to dynamic daylight, a combination of radiation from direct sunlight and diffuse skylight, which has created a flow of variations in light, in terms of direct:diffuse distribution, intensities and spectrum. This study investigates the qualities of the flow of light in an office after adding ceiling-mounted spotlights (32° tilt angle) to traditional diffuse ceiling panels. The intention is to create a flow of task light – a light-zone at each work-plane – complementing the directionality of the natural daylight inflow from the windows. An experiment was carried out in an office, in two parts. Four ratios of direct:diffuse light were tested by 30 people. Then one ratio was tested in five combinations of high, neutral and low color temperatures by 15 people in two daylight situations: overcast and clear sky. The visual light quality and perceived atmosphere of the office environment was tested through questionnaires, reaction cards and semi-structured interviews. The direct flow of light is recommended to be more than 15% of the total illuminance at the work-plane to provide the distinct visual appearance of modeling and a cozier atmosphere, which is preferable for socializing, and less than 45% to avoid glare and high contrast for visual tasks. Direct warm and diffuse cool lighting were perceived as the most natural but were not always preferred. There is an indication of slight preference for cooler ambient lighting in clear sky situations and warmer ambient lighting in overcast situations. Especially the preference in relation to sky conditions needs to be further investigated. A field study will implement these findings in a double dynamic lighting concept responding to daylight level and sky character. Strong individual preferences for combinations of color temperatures was identified, this open up new research areas for personalized flows of light in future dynamic lighting designs.

摘要

人类的感知和视觉已经随着动态日光而进化，日光是直射阳光和漫射天光的组合，在直接：漫射分布、强度和光谱方面产生了光的变化流。这项研究调查了在传统漫射天花板面板上添加天花板安装的聚光灯（32° 倾斜角）后办公室中光流的质量。目的是创造一个工作光流——每个工作平面上的一个光区——补充从窗户流入的自然日光的方向性。实验在办公室进行，分为两部分。由 30 人测试了四种直接光：漫射光的比率。然后由 15 人在两种日光情况下在高色温、中性色温和低色温的五种组合中测试了一种比率：多云和晴朗的天空。通过问卷调查、反应卡片和半结构化访谈来测试办公环境的视觉光质量和感知氛围。建议直射光占工作平面总照度的15%以上，以提供造型鲜明的视觉外观和更舒适的氛围，有利于社交，低于45%以避免眩光和视觉任务的高对比度。直接暖光和漫射冷光被认为是最自然的，但并不总是首选。有迹象表明，在晴朗的天空情况下更偏爱较冷的环境照明，而在阴天情况下则偏爱较暖的环境照明。特别是与天空条件相关的偏好需要进一步研究。一项实地研究将在响应日光水平和天空特征的双动态照明概念中实施这些发现。确定了对色温组合的强烈个人偏好，这为未来动态照明设计中的个性化光流开辟了新的研究领域。